/*
 * Copyright (C) 2009 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import java.util.Spliterator;
import java.util.Spliterators;

/**
 * Implementation of {@link ImmutableList} used for 0 or 2+ elements (not 1).
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
class RegularImmutableList<E> extends ImmutableList<E> {
    static final ImmutableList<Object> EMPTY = new RegularImmutableList<Object>(new Object[0]);

    private final transient Object[] array;

    RegularImmutableList(Object[] array) {
        this.array = array;
    }

    @Override
    public int size() {
        return array.length;
    }

    @Override
    boolean isPartialView() {
        return false;
    }

    @Override
    int copyIntoArray(Object[] dst, int dstOff) {
        System.arraycopy(array, 0, dst, dstOff, array.length);
        return dstOff + array.length;
    }

    // The fake cast to E is safe because the creation methods only allow E's
    @Override
    @SuppressWarnings("unchecked")
    public E get(int index) {
        return (E) array[index];
    }

    @SuppressWarnings("unchecked")
    @Override
    public UnmodifiableListIterator<E> listIterator(int index) {
        // for performance
        // The fake cast to E is safe because the creation methods only allow E's
        return (UnmodifiableListIterator<E>) Iterators.forArray(array, 0, array.length, index);
    }

    @Override
    public Spliterator<E> spliterator() {
        return Spliterators.spliterator(array, SPLITERATOR_CHARACTERISTICS);
    }

    // TODO(lowasser): benchmark optimizations for equals() and see if they're worthwhile
}
